As Muslims we are obligated to send blessings upon the Prophet (ﷺ) and Allah (سبحانه و تعالى). However though, people will sometimes abbreviate these blessings when they are mentioned. and I will admit, I used to be one of these people, until I learned not to do this on Abu Khadeejah's website. This is something that isn't proper.
From the Sunnah of the Prophet (ﷺ) is that if someone invokes his blessings in full, Allah (subhana wa ta'ala) will write his blessings upon him tenfold due to it:
This means that the believing Muslim must write the blessings in full (سبحانه و تعالى or عز و جل when mentioning Allah), (ﷺ when mentioning the Prophet of Allah).
May Allah bless you, and shukran.
1. Muslim 408, An-Nasā’ī 1296 and others : Abu Khadeejah